COVER 2018124 - Caterpillar

TYPICAL AIR START INSTALLATION
4. Air start control valve.The air from the supply goes to relay valve (2). The starter control valve (4) is connected to the line before the relay valve (2). The flow of air is stopped by the relay valve (2) until starter control valve (4) is activated. The air from starter control valve (4) goes to piston (10) behind pinion (8) for the starter. The air pressure on piston (10) puts spring (11) in compression and puts pinion (8) in engagement with the flywheel gear. When the pinion is in engagement, air can go out through another line to relay valve (2). The air activates relay valve (2) which opens the supply line to the air starting motor.
AIR STARTING MOTOR
5. Air inlet. 6. Vanes. 7. Rotor. 8. Pinion. 9. Gears. 10. Piston. 11. Piston spring.The flow of air goes through the oiler (3) where it picks up lubrication oil for the air starting motor.The air with lubrication oil goes into the air motor through air inlet (5). The pressure of the air pushes against vanes (6) in rotor (7), and then exhausts through the outlet at bottom of air motor. This turns the rotor which is connected by gears (9) and a drive shaft to starter pinion (8) which turns the engine flywheel.When the engine starts running the flywheel will start to turn faster than starter pinion (8). Pinion (8) retracts under this condition. This prevents damage to the motor, pinion (8) or flywheel gear.When starter control valve (4) is released, the air pressure and flow to piston (10) behind starter pinion (8) is stopped, piston spring (11) retracts pinion (8). Relay valve (2) stops the flow of air to the air starting motor.To maintain the efficiency of the starting motor, flush it at regular intervals. Put approximately 0.5 liter (1 pt.) of diesel fuel into the air inlet of the starting motor and operate the motor. This will remove the dirt, water and oil mixture (gummy coating) from the vanes of the motor.Electrical System
The electrical system has three separate circuits: the charging circuit, the starting circuit and the low amperage circuit. Some of the electrical system components are used in more than one circuit. The battery (batteries), circuit breaker, ammeter, cables and wires from the battery are all common in each of the circuits.The charging circuit is in operation when the engine is running. An alternator makes electricity for the charing circuit. A voltage regulator in the circuit controls the electrical output to keep the battery at full charge.The starting circuit is in operation only when the start switch is activated.The low amperage circuit and the charging circuit are both connected to the same side of the ammeter. The starting circuit connects to the opposite side of the ammeter.Charging System Components
Alternator
The alternator is driven by V-type belts from the crankshaft pulley. This alternator is a three phase, self-rectifying charging unit, and the regulator is part of the alternator.This alternator design has no need for